This invention relates to a hydraulic material composition and more particularly to a hydraulic material composition having high strength above all an improved bending strength.
It is already known from PCT Laid-open Publication No. 55-500863 or Japanese Patent Publication No. 59182/1985 to produce a hardened body of high strength and dense structure by admixing a hydraulic inorganic material with ultra-fine particles smaller in size by one or two orders than the inorganic material, and also with a superplasticizer. It is also known from PCT laid-open Publication No. 61-502603 to use stainless steel particles as aggregate in combination with a Portland cement type hydraulic material. Although these conventional hydraulic material compositions have excellent structural density as compared with the conventional mortar or concrete compositions, they may be exploded due to water vapor at elevated temperatures. Thus, it cannot be said to be heat-resistant and the products obtained from these hydraulic material compositions are used in the range of 250 to 400.degree. C. at most. In preparing molded products from these hydraulic material compositions, the problem of cracking due to thermal stress is yet to be solved. Both of the conventional hydraulic material compositions also suffer from a drawback that the bending strength thereof is lowered by dry curing at higher than 100.degree. C.
A hydraulic material composition for castable refractories, also known in the art, poses no problem in heat resistance, but it is difficult to provide the composition with high strength, especially high bending strength. It is also difficult to provide the composition with transferability by cast molding while maintaining excellent fluidity. There are also other problems to be solved with the known composition, for example, considerable loss in strength at a medium temperature range of 400 to 900.degree. C. and unstable transition temperature of hydrate formation which is at or close to room temperature.
As described above, a number of problems must be overcome if it is desired that a hydraulic material composition having excellent workability to permit cast molding at ambient temperatures and excellent transferability to the cast surface as well as superior heat resistance and high strength characteristics be produced from the hydraulic material.